JP2023526148A - Sol coating method - Google Patents

Abstract

A method comprising the steps of providing a sol comprising a solvent, contacting the sol with a precipitation initiator different from the solvent to initiate precipitation of the sol, and applying the sol to a product during precipitation. The method of the present invention can be used with a sol comprising a solvent, a metal alkoxide, and optionally a biopolymer and/or a catalyst, including metal-containing alkoxides, metal-containing organically modified alkoxides, metalloid-containing alkoxides, and metalloids. are included in the term "metal alkoxide". Apparatus for use in the method is also disclosed including a first storage vessel, a second storage vessel, one or more pumps, and one or more delivery means. [Selection diagram] Fig. 1

Description

Detailed description of the invention

The present invention relates to the application of colloidal solutions (known as sols) to products, and methods of doing so. More particularly, the invention relates to methods of using sols to impart desired properties to products.

Paper, cardboard, wood, and other materials are commonly used as packaging for commercial goods. Product material properties, such as the permeability of packaging materials to water, oil, and other fluids, can be controlled by utilizing impermeable plastic materials or composites. Many industries, such as the food and beverage sector, sometimes apply plastics to otherwise permeable media to facilitate retention of liquid products within certain packages. Similar methods may be used to prevent fluid ingress into articles that may be compromised by exposure to water, air, or other fluids. The plastic materials used for these applications are generally produced from hydrocarbon feedstocks, and the production of plastic materials entails environmental costs. The materials or chemicals used to manufacture these plastics and related by-products can be toxic. Some plastics can degrade over time to produce microplastics or release potentially harmful chemical species through use. Accordingly, there continue to be health and environmental concerns regarding many common packaging materials.

In general, commercial manufacturing activities aim at producing the maximum quantity of product at the lowest cost without sacrificing the delivery of quality deemed acceptable or desired by the market in which the product is sold. is. Plastics remain a low-cost commodity, and since the widespread adoption of plastics in manufacturing in the 1940s and 1950s, manufacturing around the world has had sufficient resources to utilize and manipulate plastic materials. A developed and efficient method was established. It is generally recognized that for a good plastic replacement technology to be accepted by the manufacturing industry, it will need to be operable at similar cost and equal or less ease of use. Therefore, there is a commercial need for environmentally friendly alternatives to plastics that can be readily adopted in manufacturing environments that offer the same benefits as plastics at a comparable cost.

Sol technology, or sol-gel technology, offers a non-toxic alternative to some plastic materials. In this context, the term "sol" means a dispersion of colloidal particles in a liquid medium. Many sols formed from small colloidal particles are substantially clear and colorless. For example, sols formed from silicon-based functional materials are generally clear and colorless. The reason is that the particles forming the sol are so small that they do not scatter light. Some sols formed from relatively large particles may be colored and/or at least partially opaque. For example, a sol formed from a titanium-based functional material may be visibly white. Sols can form coating compositions that are impermeable, and/or antimicrobial, and/or otherwise functional when applied to a variety of materials. Therefore, the sol can be used as a barrier and/or antimicrobial coating composition, and other properties such as hydrophobic, oleophobic, antifouling, biofouling, antifouling, light transmissive, and adhesion promoting properties. Functionality can be realized. The sol may contain readily available natural materials. This ensures that the resulting sol is inexpensive. Furthermore, the sol can be applied directly to the surface, i.e. the surface does not have to go through a special preparation process. This ensures that the sol is easy to use. Additionally, some sols have been shown to provide durable and heat resistant coatings. This demonstrates that the sols are capable of forming resilient and long-lasting functional coatings.

The inventors of the present invention have recognized that lesser amounts or concentrations of the sol can be utilized to impart desired properties to the product that are also achieved using the sol on a 100% basis. . It would have been originally assumed that smaller amounts of sol would not be able to form the extensive crosslinked network that might be necessary to achieve desired functionality such as impermeability. It is surprising that the beneficial functional properties are retained using a lower amount or concentration of the sol.

The inventors of the present invention have further recognized that it is possible to utilize the sol during the precipitation process to impart functional characteristics to the product or coating on the product. Using a precipitation initiator to initiate precipitation of the sol destabilizes the previously stable colloidal gel suspension. The inventors believe that the sol applied to the product early in the precipitation process has functionality equivalent to the functional network structure formed when the stable sol is used without further additives or ingredients. It is understood that it further forms a sexual network structure. Sols during the precipitation process may exhibit, at least temporarily, an increase in the number of active sites due to the formation of reactive particles, partially dispersed gels, and sol during precipitation. Thus, the sol is used with a precipitation initiator, and the sol during precipitation is used to form the product, provided that the precipitated sol is applied to the product after the precipitation process is initiated and before the precipitation process is completed. It is possible to coat or add functionality to the product. Additionally, the sol during precipitation can be used on a less than 100% basis and can retain a surprising level of functionality due to the increased number of active sites formed during the precipitation process.

According to one aspect of the invention, (i) providing a sol comprising a solvent, (ii) contacting the sol with a precipitation initiator different from the solvent to initiate precipitation of the sol, and (iii) A method is provided comprising the step of applying the precipitating sol to a product.

According to another aspect of the invention, a first storage tank, a second storage tank, one or more pumps, and a sol and precipitation initiator stored in each of the first and second storage tanks is provided for use in the methods described herein, comprising one or more means for applying to a product.

It is an example of a method of using a sol to impart one or more desired properties or characteristics to a product or article. 1 is a scanning electron microscope (SEM) image of the surface of an article to which a sol during precipitation has been applied according to the method disclosed herein. FIG. 2 is a schematic representation of the surface of the product after application of the precipitating sol; 1 is an example of a device that can be used in the methods described herein to use a sol to impart one or more desired properties or characteristics to a product or article. FIG. 10 is an example of another device that can be used in the methods described herein, wherein the device is used to form a sol prior to contact with the precipitation initiator.

[Detailed description]
A sol can be formed by dispersing one or more materials of suitably small particle size in a solution. Some sols may further comprise additional ingredients such as catalysts or functional ingredients. A sol suitable for use in the method of the present invention can be any sol that can be applied, coated, or incorporated into the product to impart beneficial properties or characteristics to the resulting product. Sols suitable for use in the methods of the present invention generally comprise functional materials and solvents. In one example, the method of the invention can be used with a sol comprising a solvent, a functional metal alkoxide, and optionally a biopolymer and/or catalyst. The term "metal alkoxide" includes metal-containing alkoxides, metal-containing organically modified alkoxides, metalloid-containing alkoxides, and metalloid-containing organically modified alkoxides. Solvents used in forming the sol may include water, one or more alcohols, any other suitable solvent, or any combination thereof. The one or more alcohols, if present, can include methanol, ethanol, butanol, ethylene glycol, isopropanol, any other suitable alcohol, and any combination thereof. Biopolymers, when present, can include starch-based polymers, hemicellulose-based polymers, cellulosic-based polymers, lignin-based polymers, chitosan-based polymers, any other suitable or modified biopolymers, and any combination thereof. . The sol may additionally or alternatively comprise one or more flours derived from natural sources. Suitable flours may include oat flour, barley flour, rye flour, wheat flour, rice flour, bamboo flour, lentil flour, chickpea flour, pea flour, corn flour, or any combination thereof. When the sol comprises a functional metal alkoxide, the alkoxide generally conforms to the general formula M(OR) _x or R _C -M(OR) _x , where "M" is Any metal that forms a hydrolyzable metal alkoxide is indicated. “R” and “R _C ” represent alkyl groups, typically 1-30 carbon atoms, which can take any suitable form, such as linear, branched, aromatic, or complex. "x" is generally equal to the valence of the corresponding metal ion "M". In one example, R can be a methyl, ethyl, propyl, or butyl group. If the metal ion "M" has a valence greater than 1, each R group can be the same. R _C represents any suitable organic group that forms and maintains a covalent bond with the metal "M" after hydrolysis of the alkoxide. In some examples, R and _RC can be the same. In other examples, R and _RC can be different. Any suitable metal alkoxide can be used. Examples of suitable metal alkoxides include Si(OR) ₄ , Ti(OR) ₄ , Al(OR) ₃ , Zr(OR) ₃ and Sn(OR) ₄ , and R _C -Si(OR) ₃ , R _{R C} -Ti(OR) ₃ , R _C -Al(OR) ₂ , R _C -Zr(OR) ₂ , and R _C -Sn(OR) ₃ . In specific examples, R can be a methyl group, an ethyl group, a propyl group, or a butyl group. In some embodiments, R _C can be a phenyl group, a cyclopentyl group, or any other suitable organic group capable of maintaining a covalent bond with the metal. The metal of the metal alkoxide can include silicon, titanium, aluminum, zirconium, tin, or any other suitable metal. In particular examples, the metal alkoxides are Ti(isopropoxy) ₄ , Al(isopropoxy) ₃ , Al(sec-butoxy) ₃ , Zr(n-butoxy) ₄ , Zr(n-propoxy) ₄ , n-propyl triethoxysilane, tetrapropylorthosilicate, titanium(IV) t-butoxide, titanium(IV) isopropoxide, triethyloxysilane, methyltriethyloxysilane, triethoxy(octyl)silane, phenyl-triethoxysilane, titanium(iv) ethoxide, triethoxy-silylcyclopentane, (3-glycidyloxypropyl)trimethoxysilane, cyclopentyltriethoxysilane, 3-amino-propyltriethoxysilane, triethoxy-3-(2-imidazolin-1-yl)propylsilane, and It may be selected from the group containing any combination thereof. In selected examples, the metal alkoxide may be selected from the group comprising tetraethoxysilane, phenyltriethoxysilane, methyltriethyloxysilane, and any combination thereof. In further selected examples, the metal alkoxide is tetrapropyl orthosilicate, titanium(IV) t-butoxide, titanium(IV) isopropoxide, triethyloxysilane, methyltriethyloxysilane, triethoxy(octyl)silane, phenyl-tri It may be selected from the group comprising ethoxysilane, titanium(iv) ethoxide, triethoxy-silylcyclopentane, (3-glycidyloxypropyl)trimethoxysilane, cyclopentyltriethoxysilane, or any combination thereof. In further selected examples, the metal alkoxides are Ti(isopropoxy) ₄ , Al(isopropoxy) ₃ , Al(sec-butoxy) ₃ , Zr(n-butoxy) ₄ , Zr(n-propoxy) ₄ , and It may be selected from the group comprising n-propyltriethoxysilane-based alkoxides, as well as any combination thereof.

The method of the invention is illustrated in FIG. The method 10 generally includes steps 11 of providing a sol containing a solvent, 12 of contacting the sol with a precipitation initiator to initiate precipitation of the sol, and 13 of applying the precipitating sol to a product.

A sol for use in the method of the present invention can be formed by dispersing a suitably small particle size functional material in a solvent and adding a catalyst. Functional materials can be particles having at least one dimension in the range of about 1 nm to 1 μm. An alternative method of making a sol that can be used in the method of the present invention involves dispersing the functional material in a solution containing the catalyst and then adding the biopolymer and/or one or more other additives. include. When the biopolymer and/or one or more other additives are present, the sol containing the functional material is generally treated for a period of time prior to the addition of the biopolymer and/or one or more other additives. may have been stored. Additional functional additives can be added at any stage during the process of making the sol. For example, in a sol containing a biopolymer, additional functional additives are added before or after dispersing the biopolymer in solution, but before adding the alkoxide, or after adding the biopolymer and alkoxide to the solution. be able to. One or more additives can be added at different stages of making the sol. Using additives to adjust the properties of the sol, for example to make it suitable for UV curing, visible light curing, or infrared curing, and/or prepared using the sol It can be used to impart additional functionality to the coating, such as color, pH sensitivity, conductivity, fluorescence. The additive used depends on the intended use of the sol. Suitable additives include photoinitiators, resins, oils, dyes (including pH sensitive dyes and fluorescent dyes), salts, surfactants, composite particles, mineral particles or other inorganic particles (carbonates, carbides, oxides). , hydroxides, nitrates, bromides, etc.), and metallic particles (including alloys and particles comprising one or more metals and one or more additional non-metallic components). Sols suitable for use in the methods of the invention may be formed without the presence of additives or biopolymers. More particularly, sols suitable for use in the methods of the present invention may be completely or substantially free of additives and/or biopolymers during formation and/or use. Furthermore, if appropriate, the sol suitable for use in the method of the invention can be formed separately from the product to which the sol is ultimately to be applied. In such instances, after formation of the sol, the sol and the product to which the sol is to be applied are combined.

By definition, sols are generally stable. Thus, the sol for use in the method of the invention can be formed at some point prior to the step of contacting the sol with the precipitation initiator. For example, the sol may be stored for up to 1 hour, up to 1 day, up to 1 week, up to 1 year, up to 10 years, or more prior to the step of forming the sol and contacting it with the precipitation initiator. However, the sol may be formed just before, less than 2 seconds, less than 15 seconds, less than 30 seconds, less than 1 minute, or less than 1 hour before the step of contacting the sol with the precipitation initiator.

A sol may be formed in geographical proximity to the precipitation initiator prior to use in the method of the present invention. Alternatively, the sol may be formed off-site from where the method is to be performed and then transported to the site. In one example, the sol can be formed at the manufacturing site in an on-line process seconds before the sol is contacted with the precipitation initiator. In another example, the sol may be formed at an independent manufacturing facility and then transported by road, rail, air, sea, pipeline, or equivalent to a geographically separate site where the sol contacts the precipitation initiator. good.

The precipitation initiator used in the method of the present invention can be any element, chemical or compound that encourages the sol to lose stability and begin to precipitate. The particular precipitation initiator selected for use in the method of the invention will depend on the nature of the sol formed in the method. In one example, a sol formed using water as a solvent generally does not begin to precipitate upon addition of further water. In this example, water is not a precipitation initiator because it does not initiate precipitation of the sol. In contrast, adding water to a sol containing an organic solvent can initiate precipitation of the sol. In this example, water would be considered a precipitation initiator. Preferably, the precipitation initiator may be liquid. Preferably, the precipitation initiator is more environmentally friendly than the solvent used in forming the sol. More preferably, the precipitation initiator is readily commercially obtainable and/or available at a lower price per mass or volume than the solvent used in forming the sol. Precipitation initiators with these characteristics provide a method by which the sol can be applied to products in both an environmentally friendly and cost effective manner. Thus, the method of the present invention is advantageous because it provides an easy way to use the sol with environmentally friendly materials in manufacturing applications at low cost (compared to using the sol itself). Therefore, the method of the present invention can be used to replace plastics in some manufacturing processes without creating an undue burden on the manufacturing industry.

In one example, if the sol includes ethanol or isopropanol and one or more functional ingredients that are insoluble in water, the precipitation initiator can include water. The water can take any suitable form and thus can initiate precipitation when mixed into the sol as a liquid. Alternatively, or in addition, water vapor may be passed over or blown through the sol to initiate precipitation. In another example, if the sol includes water and one or more functional ingredients that are insoluble in ethyl acetate, the precipitation initiator can include ethyl acetate. However, precipitation initiators are not limited to alternative solvents and can be solids, liquids, or gases that otherwise disrupt the stability of the sol. In one example, a precipitation initiator can be an acid or base that changes the pH of the sol to a pH that transitions the sol from the sol to a colloidal suspension that is unstable and begins to precipitate. In another example, a precipitation initiator can be one or more materials that increase the concentration of dispersed molecules in the sol such that the sol transitions above the critical solidification concentration of the sol. In a further example, the precipitation initiator can be an ionic solid that, when added to the sol, disrupts the charge balance of the sol sufficiently so that the sol begins to precipitate. Oil may be used as a precipitation initiator. Those skilled in the art, with the aid of this disclosure, will be able to readily identify suitable precipitation initiators.

A precipitation initiator may comprise one or more functional additives, or may consist essentially of one or more functional additives. Additives can be used to tailor the properties or characteristics imparted to the product by the addition of the sol. For example, additives may be added to the liquid to make the product suitable for ultraviolet curing, visible light curing, or infrared curing, and/or coatings formed on the product may have color, pH sensitivity, or conductivity properties. or additives may be used to impart additional properties such as fluorescence. The additives used will depend on the intended use of the product. Suitable additives include photoinitiators, resins, oils, dyes (including pH sensitive dyes and fluorescent dyes), salts, surfactants, composite particles, mineral particles or other inorganic particles (carbonates, carbides, oxides). , hydroxides, nitrates, bromides, etc.), and metallic particles (including alloys and particles comprising one or more metals and one or more additional non-metallic components).

Contacting the sol with a precipitation initiator initiates precipitation of the sol and formation of a "precipitating sol". Preferably, the precipitation initiator and sol are selected such that precipitation occurs over the next 5 minutes, 10 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 5 hours, or more after contact. be done. Precipitation is considered complete when the mixture of sol and precipitation initiator is no longer capable of imparting the desired functionality to the product to which it is applied. Thus, without being bound by theory, the sol during precipitation can be considered a transient nanodispersion, microdispersion, or suspension. In one example, precipitation can be considered complete when it is observed that the sol has settled sufficiently to begin settling on the bottom of the container in which the sol and precipitation initiator were mixed. In another example, precipitation can be considered complete when the sol has completely settled to the bottom of the container in which the sol and precipitation initiator were mixed. Also, sol precipitation can be tracked and evaluated using analytical techniques such as optical analysis, turbidimetric techniques, and the like.

The amount of precipitation initiator required to initiate precipitation of the sol depends on the specific properties of the sol and the precipitation initiator selected. In one example, if the precipitation initiator is a liquid, the amount of precipitation initiator required can be the amount needed to break up the solvent system of the sol to initiate precipitation. In another example, if the precipitation initiator is a solid, the amount of precipitation initiator required can be the amount necessary to disrupt the charge balance of the sol such that the sol loses stability and begins to precipitate. . In some circumstances it may be possible and advantageous to use a minimal amount of precipitation initiator, but generally the active sol is diluted so that it can be applied to a larger amount of product. It is advantageous to utilize precipitation initiators that are available in large quantities at low cost. The ratio of sol to precipitation initiator can be from 1:500 to 100:1. In one example, the ratio of sol to precipitation initiator can be from 1:200 to 1:2. In a further example, the ratio of sol to precipitation initiator can be from 1:100 to 1:10. In yet another example, the ratio of sol to precipitation initiator can be from 1:100 to 1:75. In another further example, the ratio of sol to precipitation initiator can be from 1:100 to 1:90.

The precipitation initiator and sol can be contacted in any suitable manner. For example, fluid mixing, convergent process flow, plunging, spraying, direct contact, transient contact, sparging, vortex mixing, blending, stirring, stirring, and the like. In some examples, the sol can be added to the precipitation initiator. Alternatively, a precipitation initiator can be added to the sol. In yet another example, the sol and precipitation initiator are brought together by moving, transporting, or flowing both the sol and precipitation initiator together.

Contacting the sol with the precipitation initiator can result in the sol forming a coating on the vessel, tank, pipe or conduit in which the contact is made, or equivalent equipment downstream of the contacting process. However, the formation of coatings may be avoided by selecting vessels, vessels, pipes, or conduits that are constructed from materials on which coatings are not formed. In one example, the sol during precipitation may form a coating on glass containers but not on plastic containers. Additionally or alternatively, a coating may be intentionally formed on the inside of a vessel, vessel, pipe or conduit. This is because subsequent contact events cannot form a further coating on top of an existing coating or add to the previous coating, thereby allowing precipitation to proceed as intended. Become. Those skilled in the art, with the aid of this disclosure, will be able to identify suitable improvements depending on the behavior and properties of the sol and the selected precipitation initiator.

After contacting the sol with the precipitation initiator, the precipitating sol, hereinafter referred to as the "mixture", is applied to one or more products to impart desired characteristics to the products. After precipitation begins, the sol gradually loses its activity as precipitation proceeds. Therefore, it may be advantageous to apply the mixture to the product before precipitation is complete, so that the mixture is applied within a period of time before the mixture loses its effective activity. It is therefore advantageous to use the mixture immediately after contacting the sol with the precipitation initiator. For example, immediately after contacting the precipitation initiator with the sol, within 2 seconds, within 5 seconds, within 10 seconds, within 15 seconds, within 30 seconds, within 1 minute, within 5 minutes, within 15 seconds The mixture can be applied to the product within minutes, within 30 minutes, within 1 hour, or any other suitable time period.

As used herein, the term "product" is intended to include intermediate, semifinished, and unfinished products, and components thereof, in addition to otherwise finished goods and articles. . For example, applying the mixture to a product can include adding the mixture to a paper pulp slurry, airlaid pulp, or dry paper pulp prior to forming paper therefrom. Applying the mixture to the article may otherwise include coating all or part of the outer surface of the finished article with the sol dispersion or suspension. Generally, the mixture can be applied to the product by any suitable method, including brushing, spraying, spray drying, spin coating, dripping, injection, transfer, water immersion, immersion, mixing, spreading, padding, and the like. Individual or multiple application methods may be utilized to apply the mixture to a single product or article, depending on the nature of the product and the desired properties and characteristics. For example, impermeable coatings are commonly applied to articles by brushing, spraying, padding, dipping, or spin coating. In one example, obtaining a bulk mass for further processing with antimicrobial activity can be achieved by blending the mixture into an intermediate material. The product can be formed from any suitable material. More specifically, the products are wood products, textile products, leather products, metal (including alloy) products, concrete products or construction materials, cardboard products, paper products or pulp products, plastic products, glass products, ceramic products, composite materials. , sand, brick, marble, soil, paint, paint products, food and beverage products, medical devices, pharmaceutical products, and combinations thereof.

Without being bound by theory, the functional characteristics imparted to products treated using a sol can result from the formation of extensive cross-links between reactive functional groups of the sol-forming components. Furthermore, the use of a sol during the precipitation process provides both a continuous coating medium originating from the sol that remains in liquid form and the presence of discrete reactive particles formed upon initiation of precipitation. The particles may perform a filling function by partially or completely blocking or obstructing otherwise porous or permeable flow channels in the surface of the product. Thus, by coating an article with a combination of a sol and discrete reactive particles, the method allows the mixture to simultaneously act as a coating, filler, and binder for porous and/or permeable materials. enable. Upon application of the mixture to the product, the precipitating sol covers the surface of the product and flows into any pores, recesses, openings, or similar features of the surface and inner layers of the product. The liquid carries the material into the porous and/or permeable material during precipitation. Any solids or sediments already present in the sol during precipitation are transported into the structure until they partially or completely occlude, thereby filling the surface pore volume of the product. Any sol that remains in the liquid phase when applied to the product coats the outside of the product, but can also penetrate the product more deeply than solid materials. After the liquid sol component penetrates the surface of the product, the sol can continue to precipitate to form a solid material in the internal matrix of the product surface. Precipitation therefore occurs at each part of the surface topography and internal structure of the product that can be reached by the liquid sol during application, but which may not be reached by the precipitating solid particles during initial direct application. Thus, after setting, the liquid sol coating surface forms a continuous coating layer in which the discrete particulates are formed before or during the application filling of the accessible pores in the surface. As the liquid sol dries, the internal void spaces are filled by further precipitation of the sol after coating or the formation of an internal coating in the internal void spaces of the product. In this way, the sol during precipitation coats the surface of the product by forming a solid in the internal structure of the surface through which the sol permeates, filling the pore volume with the precipitation material and bonding the materials together. Such bonding, filling, and Coating is generally not possible. It is generally not feasible to fill both internal voids and surface pores with particulates. Furthermore, bonding, filling and coating with a complete precipitation coating is not feasible. This is because the functional ingredient is a solid and cannot penetrate beyond the topography of the product to which the full precipitation coating is applied. Similar results may be obtained by utilizing solid functional additives dispersed in a liquid medium, since solid functional additives cannot penetrate beyond the surface topography of the product. Depending on the sol used in combination with the methods described herein, the precipitating material may be in the form of discrete particles or in the form of a partial gel. Also, the use of a sol mixture during precipitation may allow the product to be coated with a thinner coating layer than would be achievable if the liquid sol alone was used without precipitation. Additionally, the use of a sol-in-precipitation mixture may also allow the formation of products in the absence of additional fillers and binders normally required to form the products. For example, using a precipitating sol mixture with virgin pulp may allow the formation of paper products without additional binders or fillers.

FIG. 2 shows a scanning electron microscope (SEM) image of a textile coated using the method described herein. The SEM image shows areas where a continuous coating 1 was formed where the sol dried during precipitation and accessible pores 2 at the surface filled with precipitated microparticles 3 . FIG. 3 shows a schematic diagram of the coating material. In FIG. 3 , the product 4 is coated with the sol during precipitation to form a coating layer 5 on the outer surface of the product 4 and on the pores 6 a of the exposed surface of the product 4 . Solids 7 originating from the sol during precipitation further fill the accessible pore spaces of the surface of the product. An inner coating 8 and further precipitates 9 are formed in the inner void space 6b when the sol penetrates the inner product structure. The sol during precipitation therefore fulfills the functions of coating 5 , filler 7 and binders 8 , 9 .

The method of the invention may comprise one or more further method steps. For example, the method may further comprise drying the precipitating sol after applying to the product. However, the sol may be passively dried in air at room temperature and no direct or indirect application of heat or energy is required to dry the sol. Thermal energy is not required in the methods disclosed herein, and thus, in one example, the methods define steps of drying, heating, and/or imparting energy to the precipitating sol when applied to a product. can be ruled out. Further optional method steps include adding one or more functional additives to the sol, precipitation initiator, or precipitating sol; heating or cooling the sol, precipitation initiator, or precipitating sol; changing the pH of the sol, the precipitation initiator, or the sol during precipitation; testing the properties or characteristics of the product or coating on the product by one or more test methods; Passing one or more gases through the surface can include. In another example, the method includes providing a second sol comprising a solvent, contacting the second sol with a precipitation initiator different from the solvent to initiate precipitation of the second sol. and applying the precipitating second sol to the product to which the first sol has been applied.

The method of the present invention is surprising, as it would otherwise have been assumed that low concentrations of sol show reduced or diminished efficiency. The method of the present invention allows the sol to impart some desired properties at concentrations as low as 1% when mixed with a suitable precipitation initiator. Furthermore, the residual activity exhibited by the sol during the precipitation process is even more surprising since the beneficial properties obtained from using the sol on a 100% basis are generally not conferred by the use of a sol that has completed precipitation. should be. These surprising effects can be demonstrated when considering the method using a sol intended to impart a water-impermeable coating. The formation of sol coatings using low concentrations of sol delivered in a precipitating medium allows water to permeate around the localized area of sol concentration by forming an isolated localized coating area on the coated object. may have previously been viewed as being able to However, Example 2 and the SEM images shown in Figure 2 demonstrated that this was not the case and that a completely impermeable layer could be formed.

The methods described herein can be performed at various scales. The method is applicable to small scale processes such as laboratories or workshops, but may also be performed on a large scale such as an industrial manufacturing site. The method may be performed manually. For example, a technician may manually mix the ingredients to form a sol, add a precipitation initiator into the manually mixed sol, and then use a hand brush to manually mix the precipitating sol into the product. can be applied. Alternatively, the methods described herein may be performed using an apparatus such as that shown in FIG.

FIG. 4 shows an apparatus comprising a first storage tank 101 and a second storage tank 102 . A first storage tank can be used to store the precipitation initiator and a second storage tank can be used to store the formed sol. However, either the sol or the precipitation initiator using either the first or the second storage tank, provided that suitable transport means exist to transport the sol or precipitation initiator as required. is assumed to be stored as necessary. The first storage tank 101 is connected to a conduit or pipe with a first pump 103 while the second storage tank 102 is connected to a conduit or pipe with a second pump 104 . The pump may be of any suitable type, design or configuration, such as a centrifugal pump or a positive displacement pump.

Pumps 103, 104 to, in use, draw the sol and precipitation initiator from the first and second storage tanks towards a mixing point 105 where the conduits or piping from each of the first and second storage tanks meet. can be operated. It is envisioned that the system at the mixing point 105 may include additional features, such as a mixing chamber, or any other suitable features for facilitating contact between the sol and the precipitation initiator. Flow from the first or second storage tanks 101, 102 can be further controlled using one or more valves 106 located in the associated lines. Any suitable type of valve can be used, including gate, spherical, plug, ball, butterfly, and diaphragm arrangements. Advantageously, the valve can be selected such that it is controllable to allow a selectable flow rate of precipitation initiator or sol through the valve for a given period of time. Therefore, the ratio of sol to precipitation initiator can be controlled. Additionally, depending on the desired ratio of sol to precipitation initiator, the pump drawing sol from storage tank 102 toward mixing point 105 is a metering pump controllable to deliver a controlled amount of sol to mixing point 105. Or it can be an infusion pump.

After contact, the precipitating sol is then directed toward one or more delivery means for applying the precipitating sol to the product 108 . In Figure 4, the delivery means is a spray nozzle 107, although alternative application means may be used.

Generally, the apparatus of Figure 4 is used in combination with a liquid precipitation initiator. However, one or more of the pumps and valves may be replaced by various suitable solids conveying systems such as screw conveyors, belts, bucket elevators, or equivalents capable of conveying the solid precipitation initiator into contact with the sol. good.

The apparatus of Figure 4 may further include a control system (not shown). The control system can be configured to cause the apparatus 100 to carry out the method of the invention. The control system can be a computer. A computer may include a processor and one or more computer-readable storage media storing instructions that, when executed by the processor, cause the apparatus to perform the methods of the present invention. The control system may receive one or more inputs from a user, such as the ratio of sol to precipitation initiator, the flow rate of material required, or the total amount of sol during precipitation to be applied to the product.

FIG. 5 shows another device 200 that can be used in the method of the invention, reference symbols 101-108 denoting the same technical features as shown in FIG. The apparatus of Figure 5 differs from that of Figure 4 in that it includes means 210 for forming the sol before it contacts the precipitation initiator. The sol forming means 210 includes a solvent storage tank 211 and a functional additive storage tank 212 . One or more pumps or conveying means (not shown) direct the solvent and functional additives to the mixing device 213 to form the sol. The sol then passes to storage tank 102, where the sol may be stored for a period of time or used immediately in the method of the present invention. If desired, additional storage vessels may be used and directed to mixing device 213 to form a sol containing additional components. It is also envisioned that the components forming the sol may be transferred to storage vessel 102 and mixed directly, if desired. Therefore, the apparatus of FIG. 5 can be used to carry out the entire method of the present invention.

The invention can be further understood with reference to the following examples.
[Example]

The following examples demonstrate various methods by which the sols can be formed.
Example 1 Formation of a sol
[To a mixture of ethanol (10 ml) and aqueous HCl (0.1 M, 2 ml) was added dropwise a silicon alkoxide precursor mixture (5.2 ml) consisting of 50% tetraethoxysilane and 50% phenyltriethoxysilane. The solution was stirred at room temperature for about 6 hours until sol formation.

Example 2 Sol Formation Cationic starch (CS; 7 mg) was dispersed in a mixture of ethanol (10 ml) and aqueous HCl (0.1 M, 1.6 ml) to produce a pH 2 solution. A silicon alkoxide precursor (5.2 ml) consisting of 100% methyltriethyloxysilane was added dropwise to the stirred solution and stirring was continued for an additional 2 hours.

Example 3 Sol Formation Chitosan (6 mg) was dispersed in a mixture of ethanol (12 ml) and aqueous HCl (0.1 M, 2 ml) to produce a pH 2 solution. A silicon alkoxide precursor mixture (6 ml) consisting of 50% tetraethoxysilane and 50% phenyltriethoxysilane was added dropwise to the stirred solution and stirring was continued for an additional 1.5 hours.

Example 4 Sol Formation Methyltriethyloxysilane (100%, 7.5 ml) was added dropwise to a mixture of ethanol (15 ml) and aqueous HCl (0.1 M, 2 ml). The solution was stirred for about 1 hour until sol formation.

Example 5 Formation of a sol To a mixture of ethanol (10 ml) and aqueous NaOH (0.1 M, 2 ml) was added dropwise a silicon alkoxide precursor mixture (5 ml) consisting of 50% triethoxysilane and 50% methyltriethyloxysilane. bottom. The solution was stirred for about 30 minutes until sol formation.

Example 6 Formation of a sol Titanium isopropoxide (9 g) was added to a mixture of ethanol (6.5 ml) and aqueous HCl (0.1 M, 1.8 ml). The mixture was stirred for about 30 minutes until sol formation.

Example 7 Sol Formation Flour (7 mg) was dispersed in a mixture of ethanol (8 ml) and aqueous NaOH (0.1 M, 2 ml) to produce a pH 13 solution. A silicon alkoxide precursor mixture (5.2 ml) consisting of 50% triethoxysilane and 50% methyltriethyloxysilane was added dropwise to the stirred solution and stirring was continued for an additional 30 minutes.

Example 8 Formation of a sol Methyltriethyloxysilane (100%, 5.8 ml) was added dropwise to a mixture of ethanol (6.2 ml) and aqueous NaOH (0.1 M, 1.5 ml). The solution was stirred for about 30 minutes until sol formation.

Example 9 Sol Formation Zirconium isopropoxide (8.5 g) was added to a mixture of ethanol (6.3 ml) and aqueous HCl (0.1 M, 1.6 ml). The mixture was stirred for about 1 hour until sol formation.

Example 10 Sol Formation Cationic starch (CS; 5 mg) was dispersed in a mixture of ethanol (10 ml) and aqueous NaOH (0.1 M, 1.5 ml) to produce a pH 13 solution. Methyltriethyloxysilane (5.2 ml) was added dropwise to the stirred solution and stirring was continued for an additional 20 minutes.

Example 11 Sol Formation Flour (5 mg) was dispersed in a mixture of ethanol (6 ml), aqueous NaOH (0.1 M, 1 ml), and methyltriethoxysilane (1 ml) to produce a pH 13 solution. A silicon alkoxide mixture (1 ml) consisting of 50% tetraethoxysilane and 50% phenyl-triethoxysilane was added dropwise to the stirred solution and stirring was continued for an additional 30 minutes.

Example 12 Sol Formation Aluminum isopropoxide (9.2 g) was added to a mixture of ethanol (6.5 ml) and aqueous HCl (0.1 M, 1.6 ml). The mixture was stirred for about 1 hour until sol formation.

The following examples demonstrate various methods of using the sol.
Example 13
Precipitation was initiated by mixing the sol of Example 1 with 200 ml of water at room temperature for 10 seconds. A white solid was observed to form in the previously clear solution. The mixture was then brushed onto the inside surface of a cardboard cup within 5 minutes of the first observable formation of a white solid. The mixture was allowed to dry on the surface of a cardboard cup.

25 ml of water was added to each of the coated cardboard cups and the uncoated control cardboard cups. It was found that water immediately seeped through the uncoated cardboard cups and leaked into the surrounding area. The 25 ml of water in the coated cardboard cup was held without observable leakage for over 1 hour, at which point observation was stopped.

Example 14
Precipitation was initiated by mixing the sol of Example 2 with 75 ml of water for 5 seconds at room temperature. A white solid was observed to form in the previously clear solution. The mixture was then sprayed onto the exposed surface of the permeable pulp plant pot within 10 minutes of the first observable formation of a white solid. The mixture was allowed to dry on the surface of the flowerpot.

50 ml of dairy ice cream was added to each of the coated and uncoated control pots and allowed to melt for 2 hours. After about 30 minutes, liquid was observed to permeate the uncoated pots, and this permeation became progressively more pronounced over the next hour. No permeation or leakage was observed in the coated pots during this period, at which point the observation was stopped.

Example 15
Precipitation was initiated by mixing the sol of Example 3 with 30 ml of water at room temperature for 5 seconds. A white solid was observed to form in the previously clear solution. The mixture was then spun onto the exposed surface of the wood tile within 12 minutes of the first observable formation of a white solid. The mixture was allowed to dry on a wooden tile surface.

Nine drops of water, approximately 0.75 ml each, were placed on the surface of a 3x3 square grid of coated wooden tiles. The process was repeated with identical uncoated wood tiles. Over the next 5-10 minutes, it was observed that the water droplets on the uncoated wood tile were absorbed by the surface of the wood tile, leaving a wet circular stain on the surface. Water droplets placed on coated wooden tiles remained on the surface for 5 hours, at which point observations were stopped.

Example 16
The coated wood tile of Example 15 was sliced in half to produce two tiles half the thickness of the original tile. The surface of each half-thickness tile that was already inside the original thicker tile was subjected to the water droplet experiment described in Example 15 above. The water droplets remained on the surface of each half-thickness tile for 2 hours, at which point observations were stopped.

Example 17
The experiment of Example 15 was repeated using the sol of Example 4 and prepainted wood tiles. It was observed that water droplets placed on uncoated painted wood tiles were slowly absorbed by the surface of the tiles over a period of 15-30 minutes. A water droplet placed on the surface of the coated wooden tile remained on the surface of the coated wooden tile for 5 hours, at which point the observation was stopped.

Example 18
Precipitation was initiated by mixing the sol of Example 6 with 30 ml of water at room temperature. After a white solid formed in the sol mixture, the square of fabric was dipped into the sol mixture for about 10 minutes. After soaking, the fabric squares were removed and dried.

Eight drops of water, approximately 0.75 ml each, were placed on the surface of the coated fabric squares. The process was repeated with a second uncoated square of fabric. It was observed that the water droplets were absorbed by the uncoated fabric squares within a period of 2-5 seconds. The water droplets on the coated fabric squares remained on the coated surface for 5 hours, at which point observation was stopped.

Claims (37)

(i) providing a sol containing a solvent;
(ii) contacting the sol with a precipitation initiator different from the solvent to initiate precipitation of the sol; and (iii) applying the sol to a product during precipitation. 2. The method of claim 1, wherein said sol comprises an alkoxide. 3. The method of claim 2, wherein said sol comprises a metal alkoxide. The method of any one of claims 1-3, wherein the precipitation initiator comprises water or ethanol. The method of any one of claims 1-4, wherein the precipitation initiator comprises one or more functional additives. The method of any one of claims 1-5, wherein the sol comprises one or more functional additives. 6. The method of claim 5, wherein the one or more functional additives comprise photoinitiators, resins, oils, dyes, salts, mineral or other inorganic particles, surfactants, composite particles, and/or metals. the method of. The method of any one of claims 1-7, wherein the sol comprises one or more biopolymers. 9. The method of claim 8, wherein one or more of said biopolymers comprises starch, modified starch, flour, or modified flour. 10. The method of any one of claims 1-9, wherein the metal of the metal alkoxide comprises silicon, titanium, aluminum, zirconium, tin, or any combination thereof. 11. The method of claim 10, wherein the metal of said metal alkoxide comprises silicon, titanium, aluminum, zirconium, or any combination thereof. 12. The method of claim 10 or 11, wherein the metal of said metal alkoxide comprises silicon, titanium, or any combination thereof. The method of any one of claims 10-12, wherein the metal of the metal alkoxide comprises silicon. The method of any one of claims 10-12, wherein the metal of the metal alkoxide comprises titanium. The alkoxide is Ti(isopropoxy) ₄ , Al(isopropoxy) ₃ , Al(sec-butoxy) ₃ , Zr(n-butoxy) ₄ , Zr(n-propoxy) ₄ , n-propyltriethoxysilane, tetra Propyl orthosilicate, titanium (IV) t-butoxide, titanium (IV) isopropoxide, triethyloxysilane, methyltriethyloxysilane, triethoxy(octyl)silane, phenyl-triethoxysilane, titanium (iv) ethoxide, triethoxy-silyl Cyclopentane, (3-glycidyloxypropyl)trimethoxysilane, cyclopentyltriethoxysilane, 3-amino-propyltriethoxysilane, triethoxy-3-(2-imidazolin-1-yl)propylsilane, and any combination thereof 4. The method of claim 3, selected from the group comprising: the alkoxide is tetrapropyl orthosilicate, titanium (IV) t-butoxide, titanium (IV) isopropoxide, triethyloxysilane, methyltriethyloxysilane, triethoxy(octyl)silane, phenyl-triethoxysilane, titanium (iv) 4. The method of claim 3, selected from the group comprising ethoxide, triethoxy-silylcyclopentane, (3-glycidyloxypropyl)trimethoxysilane, cyclopentyltriethoxysilane, or any combination thereof. The alkoxide is Si(OR) ₄ , Ti(OR) ₄ , Al(OR) ₃ , Zr(OR) ₃ , Sn(OR) ₄ , _RC -Si(OR) ₃ , RC- _Ti (OR) ₃ , R _C -Al(OR) ₂ , R _C -Zr(OR) ₂ , and R _C -Sn(OR) ₃ , or any combination thereof. Method. The alkoxide is Ti(isopropoxy) ₄ , Al(isopropoxy) ₃ , Al(sec-butoxy) ₃ , Zr(n-butoxy) ₄ , Zr(n-propoxy) ₄ and n-propyltriethoxysilane system 4. The method of claim 3, selected from the group comprising alkoxides, and any combination thereof. 4. The method of claim 3, wherein said alkoxide is selected from the group comprising tetraethoxysilane, phenyltriethoxysilane, methyltriethyloxysilane, and any combination thereof. The method of any one of claims 1-19, wherein the solvent comprises one or more organic solvents. 21. The method of claim 20, wherein one or more of said organic solvents comprise alcohols. 22. The method of claim 21, wherein said alcohol is selected from the group comprising methanol, ethanol, isopropanol, butanol, ethylene glycol, or any combination thereof. A method according to any preceding claim, wherein the precipitating sol is applied to the product within 15 minutes of contacting the sol with the precipitation initiator. A method according to any preceding claim, wherein the precipitating sol is applied to the product within 15 seconds of contacting the sol with the precipitation initiator. A method according to any preceding claim, wherein the ratio of sol to precipitation initiator is from 1:200 to 1:2. A method according to any preceding claim, wherein the ratio of sol to precipitation initiator is from 1:100 to 5:100. A method according to any one of the preceding claims, wherein the precipitating sol is applied to the product to form a coating on the product. The said products are wood products, textile products, leather products, metal (including alloy) products, concrete products or construction materials, cardboard products, paper products or pulp products, plastic products, glass products, ceramic products, composite materials, sand, 28. The method of any one of claims 1-27, wherein the method is selected from the group comprising bricks, marble, soil, paints, painted products, food and beverage products, medical devices, pharmaceutical products, and combinations thereof. A method according to any one of the preceding claims, wherein the precipitating sol is mixed with the product. A method according to any one of the preceding claims, wherein the precipitating sol is applied to the product by brushing. A method according to any preceding claim, wherein the precipitating sol is applied to the product by spraying. 32. The method of claim 31, wherein the precipitating sol is applied to the product by a spray drying technique. A method according to any one of the preceding claims, wherein the precipitating sol is applied to the product by means of a roller. A method according to any one of the preceding claims, wherein the sol is formed less than 5 minutes before the step of contacting the sol with the precipitation initiator. A method according to any preceding claim, further comprising drying the product after application of the precipitating sol. A method according to any one of the preceding claims, wherein the product is not actively heated in order to dry the product after application of the precipitating sol. a first storage tank;
a second storage tank;
one or more pumps;
and one or more delivery means for applying the sol and the precipitation initiator to the product, respectively stored in each one of the first storage tank and the second storage tank. Apparatus for use in the method of any one of Claims 1 to 3.

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